Fused cutout



J1me 1940- G. L. CARLISLE FUSED CUTOUT Original Filed March 15, 1935 2 Sheets-Sheet 1 June 11, 1940. G. 1.. CARLISLE FUSED CUTOUT Original Filed March 13, 1935 2 Sheets-Sheet 2 Patented June 11, 1940 UNITED STATES PATENT OFFICE 2.204.300 i rusnn cu'rou'r poration of Delaware Original application March 13. 1935. Serial No. 10.040, now Patent No. 2,088,152, dated July Divided and this application Februmy 12. 1987, Serial No. 125,503

I Claims. (Cl. 200-114) intact, and drops into an inoperative position upon the blowing of the fuse unit. An object is to provide an enclosed dropout fused cutout including a housing and a pivotally supported door for closing the housing, the fuse assembly being supported by vthe door and, in turn, supporting the door in closed position only so long as the 20 fuse unit remains intact. A further object is to provide a fused cutout including a housing in which spaced terminals are mounted. a fuse assembly adapted to be supported by said terminals and including elements movable upon a blowing of the fuse unit to release the fuse assembly from the upper terminal, and a door for the housing; the fuse assembly being supported by the door and, in turn, supporting the door in closed position so long as the fuse unit remains intact.

These and other objects and advantages of the invention will be apparent from the following specification when taken with the accompanying drawings in which: Fig. 1 is a vertical section through an embodiment of the invention;

Fig. 1a is a fragmentary perspective view, partly in section, of a fuse unit;

Fig. 2 is a fragmentary section showing the latching terminal and latch in openingposition; Fig. 3 is a side elevation of the assembly; Fig. 4 is an inside view of the door and fuse assembly;

Fig. 5 is a front view, with parts in section, of the fuse box;

Figs. 6 and 7 are sections on lines 88 and l-l, respectively, of Fig. 4;; and

Figs. 8 and 9 are perspective views, respectively, of the lower and the upper terminal members. In the drawings, the reference numeral 30 identifies a housing of ceramic or other insulating material that is carried by a supporting strap 30' that, preferably, is so shaped that the casing or housing has a slight forward inclination to facilitate the automatic dropping of the door or closure 3| when the fuse blows. One or both side walls of the casing are provided with hooded openings 32 for the introduction of the wires which are to 'be secured to the upper and lower 5 terminals of the fused cutout.-

The upper terminal comprises a substantially rigid casting of approximately U-form, the central portion 33 of the casting being rigidly bolted to the back wall of the casing and the spaced m legs 34 of the casting terminate in notched ends that provide downwardly opening-seats 35, the upper ends 36 of the terminal legs being forwardly inclined to guide the end of a fuse assembly into the seats. u

The lower terminal is also of approximately U-shape and has a central section 31 which is rigidly secured, at its upper end, to a plate 38 ofbronze or other appropriate resilient material, and a stud bolt 38 passes through the spring plate and lower portion 40 of the terminal to 20 mount these parts on the back wall of the casing. The nut ll is not drawn down tightly on bolt 39 and the adjacent portion 40 of the terminal is convex, thus permitting a limited rocking movement of the terminal upon the bolt. 25 The side arms of the terminal 42 are deeply notched by arcuate slots 43 to provide a pivotal seat for the fuse assembly. Both terminals are provided with tubular portions 44 into which screws 45 extend to clamp the conductors to the 30 terminals. A name plate 46 may be secured to the lower terminal.

The door II has an integral pull ring and is preferably formed of amolded synthetic resin, the inner face of the door being deeply grooved 35 to provide a recess, between the opposed flanges 41, in which the expulsion tube 48 is mounted. The upper conductive collar 49 is fixed to the tube 48 and has lugs 50 which are fixed to flanges ll by screws. The inner side of collar 49 has a pair 40 of cars 5| in which the cover 52 is pivotally mounted, the cover having a latch pin or crossbar 53 which engages in the seat 35 of the upper terminal to retain the door in closed Position so long as the cover 52 is closed upon the upper end 45 of the expulsion tube.

The lower conducting member is an arcuate strap 54 which is bolted to 'thecover 3| and has extensions or hubs 55 for pivotally mounting the door and fuse assembly in the journal slots 43 of 50 the lower terminal. The strap carries a bolt and wing nut 56 for clamping the lower end of the removable fuse to the strap. A washer having an extension 61 is preferably provided to prevent any loosening of this clamped connetiom-the 65 extension being received between spaced ears on the lower face of the strap. The fuse may be of the explosive type, Fig. la, and take the form of a cartridge having a conductive base 20 and insulating shell 2| housing an explosive charge 22 that surrounds the ignition wire 23. The ignition wire is connected between the base 20 and a terminal wire 24, and the parts are retained in place by a wad 25 and wax plug 26.

The pivotal axis of the cover 52 of the fuse assembly is so positioned, with respect to the latch pin 53 and the hubs 55, that pressure exerted along the plane passing through these parts tends to hold the cover in closed position. The spacing of the terminal seats is slightly less than the distance from the lower face of hubs 55 to the upper face of the latch pin 53 when the cover is closed. The lower terminal is therefore rocked downward, against the force of the spring plate 38, when the door 3i is moved into closed position. The door may be readily closed, however, by a quick upward swing about the hubs 55, and the spring plate 38 then yieldingly locks the door in closed position.

When the fuse blows, the pressure within the expulsion tube 48 rocks the cover 52 into open position, as shown in Fig, 2, and this movement carries the pivot point of the cover through a plane which extends through the latch seats 35 and the journal slots 43, thus allowing the momentarily increased stress in the spring plate II to cooperate with gravity to force the door ll into open position. The dotted lines in Fig. 1 illustrate the door in an intermediate position but it will be understood that the door swings into a vertical position when fully open. To refuse the device, the door is lifted from the lower terminal, the broken fuse wire and the cartridge are removed, and the new fuse cartridge is inserted without removing the expulsion tube from the door.

The contact surfaces of the conducting members on the expulsion tube and on the terminals may be machined to somewhat different curvatures to provide linecontact engagements. The door and fuse assembly constitute the blade member of a fused switch since the door may be opened by a fuse puller inserted in the ring of door 3i to open the circuit between the upper and lower terminals.

While I have described a construction including an explosive type of fuse and releasing latch which eliminates all mechanical strain on the fuse element, it will be apparent that the fuse assembly may be of the so-called toggle lever type in which the assembly is held in operative position between the spring-pressed terminals only so long as the fuse unit remains intact.

The invention has a number of advantages over prior types of enclosed cutouts. The automatic dropping of the fuse assembly provides a wide separation of the conductive elements which results in a positive interruption of the circuit, and

the dropping of the door affords a. visual indication which facilitates the identification of the particular circuit that has been opened by the blowing of a fuse unit.

While I have described a preferred embodiment of the invention, it is to be understood that changes may be made in the construction of the several parts, and in their relative sizes, shapes and relationships without departure from the spirit of my invention as set forth in the following claims.

I claim:

1. A fused cutout comprising an insulating casing having an open front, a pair of vertically spaced terminals supported by and within said casing, means on the lower terminal for removably and pivotally supporting a fuse assembly.

. a fuse assembly pivotally mounted on the lower terminal and including an upper conductive member for engagement with the upper terminal, and a door secured to said fuse assembly for closing said casing when the fuse assembly is in operative position between said terminals; said fuse assembly including a fuse unit and means displacing upon the blowing of said fuse unit for releasing said fuse unit from the upper terminal.

2. The combination with a pair of vertically spaced terminals, and a dropout fuse assembly pivotally supported by the lower terminal and maintained in engagement with the upper terminal only so long as the fuse unit remains intact, of a casing of insulating material having an open front and means supporting said terminals on the rear wall of the casing, and a door for the open front of said casing secured to said fuse assembly, whereby said door drops automatically to open position upon the blowing of the fuse unit.

3. In a dropout fused cutout, a casing of insulating material having an open front, means for supporting said casing in forwardly inclined position, a pair of vertically spaced terminals carried by the rear wall of the casing, means on the lower terminal for removably and pivotally supporting a fuse assembly, spring means associated with one terminal for urging said terminals towards each other, and a fuse assembly adapted to be pivotally supported on the lower terminal; said assembly including an expulsion tube, a conductive member at each end of said tube for electrical connection to the respective terminals, a fuse unit connected between said conductive members, means displaceable upon the blowing of thefuse unit for releasing the upper conductive member from the upper terminal, and a door connected to said fuse assembly for closing the open front of said casing when said fuse assembly is in operative position between said terminals.

4. A dropout fuse as claimed in claim 3, wherein the engaging surfaces of said terminals and said conductive members are surfaces of different curvature, whereby the contact engagement of cooperating surfaces is restricted to less than a full surface engagement.

5. An enclosed cutout comprising a' casing of insulating material having an open front, a pair of vertically spaced terminals supported by the rear wall of said casing, a spring plate for urging one terminal towards the other, means on the lower terminal for pivotally supporting a fuse assembly, a fuse assembly pivotally supported on said lower terminal and including an upper conductive member for wedging engagement with said upper terminal, a fuse included in said assembly and electrically connected between said upper conductive member and a lower conductive member engaging said lower terminal, and a door carried by said fuse assembly for closing said casing when said fuse assembly is in operative position between said terminals.

6. An enclosed cutout as claimed in claim 5, wherein said upper terminal is a rigid unit rigidly secured to said casing, and said lower terminal is secured to said spring plate, and means is proamasoo vided for pivotally securing said spring plate to said casing.

7. In a circuit breaker, the combination with a vertically arranged tubular insulating member having conductive members at the opposite ends thereof, a fuse extendingthrough said insulating member and electrically connected between said conductive members, a closure for the upper end of said insulating member, said closure'retaining the adjacent end of said fuse in engagement with the associated conductive member, and supporting means on said conductive members for reception in a pair of terminal seats, of a pair of vertically spaced terminals having portions for defining seats which open towards each other.

for receiving the respective supporting means of said conductive members, the lower terminal including spring meansyieldingly urging said seats towards each other to exert a clamping force upon the insulating member seated between the same, and means actuated by the blowing of said fuse to effect a relative displacement of one supporting means and its associated seat to initiate the removal of said insulating member from the upper terminal seat, whereby the clamping force exerted by said spring means cooperates with gravity to effect a rapid removal of the insulating member from the upper terminal seat.

8. A circuit breaker of the type including a casing within which terminals are mounted in vertically spaced relation, and the door of said casing carries a fuse assembly, said fuse assembly having portions engaging seats, on. the respective terminals, characterized by the fact that the seats on said terminals open towards each- -an expulsion tube mounted on said door, conductive members at the opposite ends of said tube for engagement with said terminal members, a fuse within said tube, said fuse having an enlarged head at its upper end and a conductingwire extending from the fuse through the lower end of the tube for connection to the lower conductive member, and a closure for the upper end of said tube, said closure being movably sup- .ported on the upper conductive member and in engagement with said enlarged head of the fuse.

10. In a fused cutout, a casing of insulating material having an open front, a pair of vertically spaced terminals within and supported by the rear wall of said casing, one of said terminals including spring means urging said termiexpulsion tube mounted upon said door, conducnals towards each other, and means on the lower terminal for pivotally supporting a fuse assembly, of a fuse assembly; said fuse assembly comprising a door for the open front of said casing, an

tive means at the opposite ends of said tube for engagement with said terminals, a fuse within said tube, said fuse having an enlarged head at its upper end and a conductive wire extending through said tube for connection to said lower conductive means, said upper conductive means including a closure for retaining the enlarged head of said fuse within said tube and for engagement with the upper terminal, and means pivotally connecting one of said conductive means to said tube, said pivotally connected conductive means being adapted for displacement upon the blowing of the fuse to release the upper conductive means from the upper terminal.

11. A fused cutout as claimed in claim l0, wherein said spring means is associated with the lower terminal'and yieldingly urges the same towards the upper terminal.

12. In a fused cutout of the dropout type, the combination with a pair of vertically spaced terminals, an insulating support for said terminals, the upper terminal comprising a pair of rigid and parallel arms forming a seat for receiving a means for pivotally supporting a fuseassembly, and spring means urging said terminals towards each other, .of a fuse assembly comprising an expulsion tube having conductive means at the opposite ends thereof for engagement with said terminals,-a fuse extending through said tube and electrically connected between said conductive members, said conductive means being spaced apart by a distance exceeding the normal spacing of said terminals, whereby said fuse unit is yieldingly retained between said terminals by a substantially axial pressure exerted thereon by ing of insulating material having an open front,

in combination with a door for said casing secured to said fuse assembly.

15. A fused cutout as claimed in claim 12, wherein said insulating support comprises a casing having an open front, said upper terminal being rigidly secured to said casing and said fuse assembly and the lower terminal including spring means urging the lower terminal towards said upper terminal.

16. In a switch type of drop out fuse of the character described, a support of insulating material, a pair of terminals carried by said support, each terminal having means for receiving a away from one of said terminals.

17. A drop out fuse of the type including an insulating support, a pair of spaced terminal port and carrying one'of said terminal members. VI

18. A drop out fuse as claimed in claim 1'7, wherein said spring means comprises a flat spring member secured to said support, and said lower terminal member is a hinge member secured to said spring member and constituting a pivotal support for the fuse unit.

19. In an enclosed fused circuit breaker, the combination with an insulating casing, a door for said casing, means pivotally supporting said door on said casing, and vertically spaced terminal means secured to said casing, of a fuse assembly carried by said door, said fuse assembly including an expulsion tube and conductive means for engagement with said terminal means when the door is closed, a fuse element extending through said tube and electrically connected between said conductive means, one of said terminal means including a flat spring for exerting pressure substantially along said fuse assembly to latch said door and fuse assembly in approximately vertical position.

20. A dropout fuse switch comprising a housing, line terminals therein, one element or a hinge therein, a removable iuse cartridge having terminal engaging elements adapted to associate with said line terminals, a removable door for the housing carried by the cartridge, a second element on said hinge associated with said cartridge, a fuse link extending through said cartridge and electrically connected between said terminal engaging elements, resilient means associated with said housing adapted to press said cartridge to prevent movement of the cartridge and door away from closed position but permitting such movement when the i'use link is blown, the gravity eflect oi the door aiding that of the cartridge upon opening movement.

GEORGE L. CARLISLE. 

